Gel and LiFePo have to have different chargers so you can’t have them hooked together when charging. And you must have different chargers for each . It’s possible to use very large diodes as an isolator between sets of batteries so they cannot cross charge. 100A diodes run $25 to $50 each, you’d need one for each battery type. HOWEVER, complications can arise because of different discharge rates. Not recommended but doable.
This is very common in backup battery situations, such as planes and boats, where the batteries can be switched in and out of the circuit, but share a common charger. The circuitry is a little different, but the same diodes. In planes/boats it’s a common charger with different or switched loads. In a solar app it different chargers with the same load.